Bootcamp Windows 10 memory BSoD

Actually your second choice is a bit odd but possibly the way to go.

macOS will certainly read (not write) from/to the default Windows 10 partition format, NTFS.

You should be able to access that partition and, assuming you know what to look for, copy the needed save files from your games to a flash drive to then transfer to your PC.

And depending on how "hands on" you are, you could theoretically remove the iMacs internal drive, stick it in an external USB enclosure and access the drive from your new Windows PC. Assuming it's not a fusion drive.

There are also utilities that will back up the Boot Camp partition, and presumably you might then be able to restore it to an external drive and access it from the new PC. That would depend on the software you use to do that and how it restores any backups it creates.

All of this depends on the Boot Camp partition being largely intact. you say nothing about that, just that it blue screens.

Also if you have a bootable Windows 10 flash drive (like the one Boot Camp created, you could boot from that and repair Windows. I use Windows 10 install media all the time to repair a blue screen error.

But there is absolutely no way to get the data off the partition without accessing it. As to get the data off of it (no matter how) you must access the partition.

Hopefully this gives you some starting points for avenues to recover your data.